This invention relates to an improved method and apparatus for separating the vaporizable hydrocarbon-containing constituents from a particulate composite. More particularly, this invention relates to a novel means to remove the vaporizable constituents from a particulate composite wherein the particulate composite is intimately comingled within a molten heat transfer material having a melting point below, and boiling point above the vaporization temperature of constituents to be recovered.
Certain apparatus for the retorting of oil shale, coal, or tar sands is well-known. In a conventional apparatus, crushed oil-bearing shale or the like is carried into a kiln or retort where the ore is heated and the kerogen products are driven off and collected. for example, U.S. Pat. No. 3,325,395 discloses a method for the recovery of oil from travelling oil-bearing shales and sands. The crushed ore is continuously conveyed through two heating zones in the apparatus in an effort to remove the hydrocarbonaceous materials therein. In another mode, U.S. Pat. No. 3,546,092 discloses an oil shale retorting method and apparatus where the crushed ore is admitted to the top of a vertical retort, and the released kerogen products recovered near the top of the retort. Also, U.S. Pat. No. 2,459,550 passes organic material through a liquid bath, the organic material being separated from the liquid bath by screens which allow the transfer of heat to the material.
Heretofore, it has been recognized that the oil shale ore, after being retorted in accordance with prior art apparatus, has contained a significant amount of hydrocarbon products which have not been recovered. With the present world-wide realization that energy resources are limited in amount and rapidly dwindling, it has become increasingly evident that new and more efficient means, as well as a more complete means of recovery of hydrocarbons from oil-bearing material must be found and practiced.
Previous apparatus has been unable to economically and completely remove all the oil and hydrocarbon constituents of shale rock or the like in part because previous retorts have been unable to rapidly and effectively transfer heat to the shale rock. The overall rate of heat transfer has been so low and inefficient in prior art apparatus as to render them economically non-competitive with drilled recovery of petroleum.
Additionally, prior proposed forms of continuously conveying apparatus have allowed air to be introduced into the retorting chamber. The recovered constituents therefore have the undesirable feature of dilution with nitrogen. Also, presence of oxygen in the combustible gas tends toward fire and explosion hazards.